code: def test_fcntl_fileno(self):
      # the example from the library docs
      self.f = open(TESTFN, "wb")
      rv = fcntl.fcntl(self.f.fileno(), fcntl.F_SETFL, os.O_NONBLOCK)
      if verbose:
          print("Status from fcntl with O_NONBLOCK: ", rv)
      lockdata = self.get_lockdata()
      rv = fcntl.fcntl(self.f.fileno(), fcntl.F_SETLKW, lockdata)
      if verbose:
          print("String from fcntl with F_SETLKW: ", repr(rv))
      self.f.close()
  
imports: import multiprocessing
  import platform
  import os
  import struct
  import sys
  import unittest
  from test.support import verbose, cpython_only, get_pagesize
  from test.support.import_helper import import_module
  from test.support.os_helper import TESTFN, unlink
label_desc: Use image node_id 4 for calling the TestFcntl obj's underlying member method code with example usage: obj.test_fcntl_fileno() without return types